Strip coiling mandrel



Dec. 23, 1958 A. H. WERNER 2,865,575

STRIP COILING MANDREL Filed Jan. 11, 1956 16/5 4171 K/QJTKQ 0,94 7057/64 fv/c/r/yars //v VEMTOl-P. ALFRED H. WERNER,

his Alforney.

United States Patent G r:

STRIP COILIN G MA'NDREL Alfred H. Werner, Youngstown, Ohio, assignor toUnited States Steel Corporatioma corporation of New Jersey ApplicationJanuary 11, 1956, Serial No. 558,574

3 Claims. (Cl. 2427842) This invention relates to an improved mandrel ofthe type used in combination with retractable wrapper rolls for coilingmetal strip.

An object of the invention is to provide an improved mandrel whichprevents the leading edge of a strip from damaging either the innerconvolutions of a coil formed on the mandrel, the mandrel itself, or thewrapper rolls.

A further object is to provide an improved mandrel whose circumferencecarries means for automatically depressing the leading edge of a stripsufliciently that it leaves no ridge which might damage any of theforegoing parts.

A further object is to provide an improved mandrel which eliminates theneed for tight engagement between the wrapper rolls and strip forstarting a coil and consequently eliminates any pounding action on thestrip as the wrapper rolls make contact.

A further object is to provide a mandrel suitable for coiling hot stripof heavier gauges than is possible with conventional mandrels.

A more specific object is to provide a mandrel whose circumference isformed as a series of alternating smooth ribs and grooves of a minimumheight or depth equal to the strip thickness, one of said groovesautomatically receiving the leading edge of the strip and depressing itsufiiciently that it leaves no ridge capable of causing damage.

In accomplishing these and other objects of the invention, I haveprovided improved details of structure, a preferred form of which isshown in the accompanying drawing, in which:

Figure l is a schematic elevational view of a typical mill in which myimproved mandrel can be incorporated;

Figure 2 is a vertical cross-sectional view of my improved mandrel; and

Figure 3 is a side elevational view of my mandrel.

Figure 1 shows schematically a portion of a typical hot strip rollingmill which includes a plurality of finishing stands 10, a set of pinchrolls 12, a mandrel 13, and retractable wrapper rolls 14 surroundingsaid mandrel. Strip S travels through the finishing stands and pinchrolls and is coiled on the mandrel. Co-nventionally the wrapper rollshold the strip on the mandrel to start the coil and thereafter guide thestrip, retracting as the coil builds up. This type of mechanism, apartfrom my mandrel, is conventional and hence is not shown in detail. For amore detailed disclosure of wrapper rolls and their operation, referencecan be made to Iverson et a1. Patent No. 1,935,092 dated November 14,1933, or Washam Patent No. 2,325,559, dated July 27, 1943, although itis apparent my invention is not limited to the specific mechanisms shownin these patents.

As shown in Figure 2, my improved mandrel comprises a cylindrical body15 and a plurality of spaced ribs 16 fixed to the circumference of saidbody. The body is shown as formed of a plurality of expandable segments,although my invention is applicable as well to solid cylindrical mandrelbodies. The ribs 16 are pui- 2,865,575 Patented Dec. 23,4958

formly spaced around the circumference leaving depressions 17therebetween and each rib extends the full length of the mandrel bodyparallel to the axis of rotation thereof. The minimum height of each ribat least equals the thickness of the strip S. Preferably the ribs have asubstantially airfoil shape in cross section to provide a smooth surfacethroughout, although other cross-sectional shapes are operable. If theribs are of rectangular cross section, for example, in service they wearto a cross section similar to that shown. It is also apparent that anequivalent structure could be produced by machining the depressions 17into the mandrel surface. Nevertheless, I prefer to fix the ribs to thebody in order that they may be removed and replaced when Worn.

In operation, as a coil is started, the conventional practice isfollowed of driving the mandrel 13 slightly faster than the strip speedto develop tension in the coil. However, frictional forces between thestrip and my improved mandrel are sufficient to hold the strip on themandrel to start the coil, and it is not necessary to use the Wrapperrolls for this purpose. In fact these rolls can be replaced with smoothfaced guide plates. When the strip S first contacts the mandrel, theleading edge automatically enters one of the depressions 17. If the edgehappens initially to overlie a rib 16, the greater speed of the mandrelproduces enough slippage that the edge enters the next depression ratherthan remaining on top of the rib. Consequently there is no ridge at theline where the leading edge lies on the mandrel, and the firstconvolution of the coil overlies a smoothly curved surface at this line.There is no tendency for the leading edge to score or otherwise damagethe inner convolutions of the coil. Likewise the force of the wrapperrolls 14 against the mandrel does not tend to damage either the mandrelsurface or the rolls themselves.

The thicker the strip, the more significant these ad vantages become. Infact I have successfully coiled hot strip of gauges too thick to coil ona conventional mandrel. Such mandrel is water-cooled, and the heat ofthe hot strip immediately converts the water to steam, which acts as alubricant. My depressions l7 allow the steam to escape and thus avoidits lubricating eifect which heretofore has limited the gauge of stripthat could be coiled.

While I have shown and described only a single embodiment of myinvention, it is apparent that modifications may arise. Therefore, -I donot wish to be limited to the disclosure set forth but only by the scopeof the appended claims.

I claim:

1. The combination with strip guiding means, of a coiling mandrel forthe strip comprising a rotatable cylindrical body having a substantiallycontinuous outer circumferential face, and a plurality of fixed ribsspaced around said circumferential face leaving a series of depressionstherebetween for frictionally holding strip on said body, each of saidribs extending the length of said body parallel to the axis of rotationthereof and being of a minimum height at least equal to the stripthickness enabling the leading end of the strip to remain substantiallyunbent and to bear against said circumferential face within any one ofsaid depressions, said guiding means at least partially surrounding saidbody.

2. The combination with a set of pinch rolls adapted to propel strip anda strip guiding means on the exit side of said pinch rolls of a coilingmandrel for the strip comprising a rotatable cylindrical body havingasubstantially continuous outer circumferential face, a plurality offixed ribs spaced around said circumferential face leaving a series ofdepressions therebetween for frictionally holding strip on said body,each of said ribs rotation thereof and being of a minimum height atleast equal to the strip thickness enabling the leading end of the stripto remain substantially unbent and to bear against said circumferentialface within any one of said depressions, and means for driving said bodyfaster than the speed at which said pinch rolls propel the strip, saidguiding means at least partially surrounding said body.

3. The combination with a set of pinch rolls adapted to propel strip anda set of retractable wrapper rolls on the exit side of said pinch rollsfor guiding the strip, of a coiling mandrel for the strip comprising arotatable cylindrical body at least partially surrounded by said wrapperrolls, said body having a substantially continuous outer circumferentialface, a plurality of ribs removably fixed to said body and spaced aroundsaid circumferential face leaving a series of depressions therebetweenfor frictionally holding strip on said body, each of said ribs extendingthe length of said body parallel to the axis of rotation thereof andbeing of a minimum height at least equal to the strip thickness enablingthe leading end of the strip to remain substantially unbent and to bearagainst said circumferential face within any one of said depressions,and means for driving said body faster than the speed at which saidpinch rolls propel the strip and enabling slippage between the leadingend of the strip and said body to position the leading end within adepression and thereafter tensioning the strip.

References Cited in the file of this patent UNITED STATES PATENTS1,492,954 Biggert May 6, 1924 1,952,181 Newill Mar. 27, 1934 2,116,121Montgomery May 3, 1938 2,733,023 Lewis et al. Jan. 31, 1956

